Time-domain single hydrophone localization in a real shallow water environment

Assuming that the time signal emitted by the source is known, a time-domain single-phone localization approach was developed by Clay((1)) and was implemented by Li and Clay in an air wedge waveguide((2)). Frazer and Pecholcs((3)) performed several numerical simulations of the time-domain single hydrophone localization with an isovelocity ocean model. In this paper, we will demonstrate the time-domain single hydrophone localization in a real shallow water environment. In November 1995, an experiment was conducted in the Gulf of Mexico. In this experiment, source and receiver were separated by approximately 21 km and were placed on the bottom along a 188-meter isobath line. An M-sequence waveform with center frequency of 150 Hz and a 3-dB bandwidth of 50 Hz was transmitted from the source and received by the receiver. We matched-filtered the received signal to get the ocean impulsive response. We used a broadband normal mode code to generate the predicted impulsive response for a source at different ranges and depths. We correlated the measured ocean impulsive response with the predicted impulsive responses and displayed the correlation output as a range-depth ambiguity surface. The peak in the range-depth ambiguity surface represents the location of the source. We successfully localized the broadband source and the dominant surface scattered energy.